This invention relates to new and useful improvements to omniphonic microphone and loud speaker systems illustrated and described in my U.S. Pat. No. 4,122,910 which is hereby incorporated by reference.
In this U.S. Patent, a regular tetrahedron construction is used for both the microphone and loud speaker components. However, that particular construction contains some directional ambiguity, which ambiguity is significantly reduced by the improvements described hereafter.
A superficial inspection of the enclosed description appears to indicate that the regular tetrahedral basis for the original invention shown in the U.S. Patent, has disappeared.
However, as will become apparent, a plane passing through the cylindrical truncations of either the microphone or the loud speaker components once again generates the regular tetrahedral shapes of the original invention. The planes also appear in the modifications made to the baffles of the side speakers.
The improvements include the following technical features:
(1) All of the transducers are shielded by cylindrical structures with elliptical end faces lying in planes oriented at 1/2 dihedral angle of the regular tetrahedron to the cylinder axis, namely, 35.degree., 16' and where the long axis of the elliptical end faces are set at 45.degree. to the horizontal. PA1 (2) The planes of the elliptical end faces of the shielding cylinders correspond or are isomorphic to the tympanic membrane of the human hearing structure. PA1 (3) The shielding cylinders of the optimal shadow omniphonic microphone component and of the isomorphic loud speaker module are isomorphic to the truncated cylinders described in the microphone and loud speaker components of U.S. Pat. No. 4,122,910 and indicated in that patent by reference character 23. PA1 (4) The planes of the end faces of a center cylinder located between the shielding cylinders in the optimal shadow omniphonic microphone component correspond to the dihedral planes of the omniphonic microphone of the above U.S. Patent and illustrated in FIG. 8 thereof. PA1 (5) The planes of end faces of a center cylinder located between the shielding cylinders in the isomorphic module of the loud speaker component correspond to the dihedral planes of the omniphonic loud speaker illustrated in FIG. 9 of the above U.S. Patent. PA1 (6) The long axes of elliptical end faces of shielding cylinders attached to room loudspeaker baffles in the speaker system are set at 45.degree. and incline downwardly to horizontal. The end faces away from the listener.
With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the best mode known to the applicant and of the preferred typical embodiment of the principles of the present invention, in which: